Silicone rubbers have excellent properties such as weatherability, electric properties, compression set at low pressure, heat resistance, and cold resistance, and therefore, it is used in various fields such as electric appliance, automobile, architecture, medicine, and foods, and in the applications such as a rubber contact in remote controller, typewriter, word processor, computer terminals, musical instrument, and the like; gasket used in buildings; rolls in copying machines such as development roll, transfer roll, electrification roll, and sheet feeder roll; dumper rubber in audio equipment; and gasket and packing for CD in computers.
Molding of the silicone rubber has been conducted, for example, by a method wherein an organopolysiloxane is thermally cured by using an organic peroxide, or a method wherein an alkenyl group-containing organopolysiloxane and an organohydrogenpolysiloxane are cured by addition reaction using a platinum catalyst.
In the meanwhile, zeolite which has regular pores can adsorb various substances in the pores. Accordingly, zeolite is used in a wide variety of applications such as deodorant and hygroscopic agent as well as water softener and separation membrane in view of selective adsorption property.
For example, JP-B H07-55287 (Patent Document 1) discloses a separation membrane wherein zeolite is dispersed in a silicone rubber matrix, and in this document, the separation membrane is used for the separation of alcohol from water by utilizing the properties of the zeolite. In this document, the film is formed without heating, and the composition used is the so called room temperature vulcanizable (RTV) silicone rubber composition which cures by condensation at room temperature condensation, and no other molding methods are described. Actually, silicone rubbers can be obtained by various molding methods, and silicone rubber tubes may be obtained by extrusion molding which is an efficient method. In the extrusion molding, addition curing wherein the curing is accomplished by hydrosilylation addition reaction under heating is occasionally employed for the curing system, and a curing speed regulation agent such as ethynylcyclohexanol have been used for the regulation of the curing by a platinum catalyst. However, in the case of the silicone rubbers having the zeolite added, extrusion molding accomplished by addition curing wherein heating step is necessary was difficult due to the adsorption of the regulation agent to the zeolite, and difficulty of balancing the surface foaming and the pot life after the addition of the curing agent. Increase in the amount of the regulation agent invites the problem of foaming in the curing while excessively low amount of the regulation agent results in the extremely short pot life despite the prevention of the foaming in the curing. Even if an acyl organic peroxide commonly used in the extrusion molding of the silicone rubber composition were used, the phenomenon of foaming in the molding can not be suppressed in the case of the silicone rubber composition having the zeolite added, and durability is also poor.
In the meanwhile, UV curing method of the silicone rubber composition is described, for example, in JP-A S55-125123 (Patent Document 2) and in JP-B S61-21963 (Patent Document 3). These documents are, however, silent about the formulation of the silicone rubber composition including the fillers such as zeolite containing water at a high content.
Prior art documents related to the present invention include Japanese Patent No. 3865638 (Patent Document 4), JP-A 2011-12264 (Patent Document 5), Japanese Translation of PCT International Application Publication No. JP-T 2010-537018 (Patent Document 6), and Japanese Translation of PCT International Application Publication No. JP-T 2011-511768 (Patent Document 7).